Tính: a) ln căn 5 + 2 + ln căn 5 - 2 b) log400 – log4; c) log 4 8 + log 4 12 + log 4 32/3
Giải thích
a) ln5+2+ln5−2=ln5+25−2=ln5−4=ln1=0;
b) log400−log4=log4004=log100=log102=2;
c) log48+log412+log4323=log48⋅12⋅323=log432⋅32=log445=5.
a) ln5+2+ln5−2=ln5+25−2=ln5−4=ln1=0;
b) log400−log4=log4004=log100=log102=2;
c) log48+log412+log4323=log48⋅12⋅323=log432⋅32=log445=5.